Serbian military honor guards participate in commemorations for victims of the Holocaust at the former World War II Nazi concentration camp of Sajmiste in Belgrade. / Darko Vojinovic/AP

by USA TODAY

by USA TODAY

WARSAW, Poland (AP) - Holocaust survivors, politicians, religious leaders and others are marking International Holocaust Remembrance Day with solemn prayers and the now oft-repeated warnings to never let such horrors happen again.

Events Sunday took place at sites including Auschwitz-Birkenau, the former death camp where Hitler's Germany killed at least 1.1 million people, mostly Jews, in southern Poland. Sunday is the 68th anniversary of the liberation of the camp by Soviet troops in 1945.

In Warsaw, prayers were also held at a monument to the fighters of the Warsaw Ghetto Uprising of 1943.

And in Rome, Pope Benedict XVI warned that "the memory of this immense tragedy, which above all struck so harshly the Jewish people, must represent for everyone a constant warning so that the horrors of the past are not repeated."

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